Oral Hygiene Device

ABSTRACT

An oral cleaning tool for an electric oral hygiene device is disclosed. The oral cleaning tool includes a housing having a head section with a head cavity for accommodating a movable oral cleaning head and a neck section with a neck cavity and a handle coupling section; a first magnetic coupling element including at least a permanent magnet or a magnetizable element being provided in the neck section for mechanical handle drive shaft connection by magnetic interaction. The first magnetic coupling element is mounted at a motion transmitter, the motion transmitter extending inside the neck cavity to the head cavity, the motion transmitter arranged so as to be movable in a linear or longitudinal direction. The motion transmitter is coupled with the oral cleaning head, the oral cleaning head arranged so as to oscillate in a rotational direction.

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation of European Patent ConventionApplication No. 11006106.6, filed Jul. 25, 2011, the substance of whichis incorporated by reference in its entirety herein.

FIELD OF THE INVENTION

The present disclosure is directed to an attachment section for an oralhygiene device, a handle section for an oral hygiene device and an oralhygiene device.

BACKGROUND OF THE INVENTION

It is known that electric oral hygiene devices, in particular electrictoothbrushes, may have detachably mounted replacement attachments suchas a replacement brush head of an electric toothbrush. It is furtherknown that the coupling between the attachment and an handle of the oralhygiene device may be by mechanical means such as a snap hook providedat the attachment that snaps into a groove provided at the handle.Mechanical couplings often have a certain clearing or gap between thecoupling partners due to tolerances between the coupling partners. Suchclearings or gaps have the tendency to generate unwanted rattling noiseduring operation of the device.

It is therefore a desire to provide an improved coupling between anattachment section of an oral cleaning tool and a handle section of anoral hygiene device and in particular an attachment section of an oralcleaning tool and a handle section that enable such improved coupling.

SUMMARY OF THE INVENTION

In one embodiment, an oral cleaning tool for an electric oral hygienedevice is provided. The oral cleaning tool includes a housing having ahead section with a head cavity for accommodating a movable oralcleaning head and a neck section with a neck cavity and a handlecoupling section; a first magnetic coupling element including at least apermanent magnet or a magnetizable element being provided in the necksection for mechanical handle drive shaft connection by magneticinteraction. The first magnetic coupling element is mounted at a motiontransmitter, the motion transmitter extending inside the neck cavity tothe head cavity, the motion transmitter arranged so as to be movable ina linear or longitudinal direction. The motion transmitter is coupledwith the oral cleaning head, the oral cleaning head arranged so as tooscillate in a rotational direction.

In another embodiment, a handle section of an electric oral hygienedevice is provided. The handle section includes a linear drive includinga drive shaft for oscillation along a longitudinal axis or in alongitudinal direction of the handle at which a second magnetic couplingelement is arranged, having at least a permanent magnet which protrudesfrom the handle and that is embedded with respect to at least threesides thereof in a hard and/or soft plastic handle body and a furthermechanical oral cleaning tool coupling section that is arranged toprovide independent coupling with the oral cleaning tool.

These and other features, aspects and advantages of specific embodimentswill become evident to those skilled in the art from a reading of thepresent disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

The embodiments set forth in the drawings are illustrative in nature andnot intended to limit the invention defined by the claims. The followingdetailed description of the illustrative embodiments can be understoodwhen read in conjunction with the following drawings, where likestructure is indicated with like reference numerals and in which:

FIG. 1 is a perspective view onto an oral hygiene device in the form ofan electric toothbrush;

FIG. 2 is a sideways longitudinal cross-sectional cut through an exampleattachment section;

FIG. 3 is a transverse longitudinal cross-sectional cut through theattachment section shown in FIG. 2;

FIG. 4 is a longitudinal cross sectional cut through an example handlesection;

FIG. 5 is a longitudinal cut through a top portion of an example oralhygiene device;

FIGS. 6A-6D show four example configurations of first and secondmagnetic coupling elements;

FIG. 7 show simulation results for the force between the couplingpartners of the four configurations shown in FIG. 6A-6D;

FIG. 8 is a cross sectional cut through a top portion of a drive shaftof an example handle section;

FIG. 9 is a cross sectional cut through a top portion of a drive shaftof an example handle section;

FIG. 10 is a cross sectional cut through a top portion of a drive shaftof a further example handle section;

FIG. 11 is a cross sectional cut through a lower portion of a motiontransmitter of an example attachment section;

FIG. 12A is a side view depiction of an example embodiment of anattachment section as proposed with the attachment housing beingtransparent;

FIG. 12B is a depiction of the embodiment of an attachment section asshown in FIG. 12A, but seen from the backside (the front side being theside where the functional element is mounted); and

FIG. 12C is a longitudinal cut through the attachment section shown inFIGS. 12A and 12B seen from the backside of the attachment section.

DETAILED DESCRIPTION OF THE INVENTION

The following text sets forth a broad description of numerous differentembodiments of the present disclosure. The description is to beconstrued as exemplary only and does not describe every possibleembodiment since describing every possible embodiment would beimpractical, if not impossible. It will be understood that any feature,characteristic, component, composition, ingredient, product, step ormethodology described herein can be deleted, combined with orsubstituted for, in whole or part, any other feature, characteristic,component, composition, ingredient, product, step or methodologydescribed herein. Numerous alternative embodiments could be implemented,using either current technology or technology developed after the filingdate of this patent, which would still fall within the scope of theclaims. All publications and patents cited herein are incorporatedherein by reference.

One aspect of the present disclosure is concerned with a connection, inparticular a detachable connection, between an attachment section and ahandle section of an (in particular electric) oral hygiene device whereat least one connection (in particular a connection established betweenmovably mounted parts that are driven during operation and are intendedfor transferring motion from a motor in the handle section to afunctional element in the attachment section) between the attachmentsection and the handle section is realized as a magnetic coupling.Mechanical couplings in general have inherently tolerance-basedclearances or gaps between the coupling partners so that the couplingpartners may move relatively to each other when the respectiveconnection is established between parts being driven during operation.Such a mechanical connection is then prone to generate unwanted noiseduring operation. A magnetic coupling can inherently be designed withless clearance so that a magnetic coupling is likely to produce lessnoise.

In some embodiments, an attachment section as proposed comprises a firstmagnetic coupling element that has at least a permanent magnet or amagnetizable element. The first magnetic coupling is arranged forestablishing a magnetic connection with a second magnetic couplingelement provided in a handle section in an attached state.

In some embodiments, an attachment section may additionally comprise anattachment housing, a functional element mounted for driven motion atthe attachment housing and a motion transmitter. The motion transmittermay on one end be coupled to the functional element to transfer motionto the functional element and on another end may be equipped with thefirst magnetic coupling element. The motion transmitter may inparticular extend in a cavity formed inside of the attachment housing.In some embodiments, the functional element may be a working elementsuch as a brush head for cleaning teeth. In some embodiments, theattachment housing may have a first coupling structure intended forestablishing a further connection with a second coupling structureprovided at the handle section.

On one hand, a magnetizable element (e.g. a magnetizable steel or ironelement) can be realized relatively cheap, and an attachment sectionintended for disposal after some period of use may then be realizedrelative cheap. This is in particular interesting in cases where thecosts of a permanent magnet would be in the same order as the costs ofthe whole attachment section. On the other hand, a permanent magnet inthe attachment section together with a permanent magnet in the handlesection can provide for a higher coupling strength then a permanentmagnet and magnetizable element combination at the same constructionvolume.

In some embodiments, the first magnetic coupling element comprises aprotective cover that protects the first magnetic coupling element fromcorrosion or abrasion. In such embodiments, the protective cover may beabrasion resistant to the extent that during a typical lifetime of theattachment section the protective cover stays intact. As an oral hygienedevice is used in a wet environment and typically with abrasive and/orcorrosive chemicals such as mouth rinses or toothpaste, a thin coatingsuch as e.g. a 10 micrometer thick gold coating may be abraded within arather short period. A protective cover made of an about 20 μm thick ormore, optionally about 30 μm or more, further optionally 40 μm or more,even further optionally about 50 μm or more metal layer, ceramic layer,glass layer or abrasion-resistant plastic or resin layer can be used. Insome embodiments, the protective cover may have a thickness of 60 μm ormore, 70 μm or more, 80 μm or more, 90 μm or more, 100 μm or more, 150μm or more or 200 μm or more, and/or any thickness within or includingthe values provided above or any ranges including or within the valuesprovided above. In some embodiments, the protective cover is realized asan essentially cup-shaped element that may be mounted by gluing,press-fitting, crimping, shrink-fitting, stamping, welding, snapping orany combination thereof. The protective cover is, in some particularembodiment, realized as a plate or disk that may be glued to themagnetic coupling element. In some embodiments, a protective cover isused that is manufactured in a deep-drawing, punch-drawing orthermoforming process.

In general, the protective cover may be designed to be abrasionresistant for a temporary period which corresponds to a typical periodof use of the attachment section. The typical period of use may be aboutthree months with three a switch-on periods of two to four minutes perday, hence the operation use period may be around 540 minutes to around1.080 minutes. However, the protective cover may be designed to beabrasion resistant for longer or for shorter periods of time. Inparticular, in some embodiments, a protective cover may be used that isabrasion resistant for much longer than 1.080 minutes, e.g. 2.000minutes, 4.000 minutes, 10.000 minutes or even longer.

In some embodiments, the first magnetic coupling element is at leastpartly accommodated in a recess or cavity provided in the motiontransmitter. In some embodiments, the motion transmitter may comprise aholder element in which the first magnetic coupling element is at leastpartly accommodated. In some embodiments, the motion transmitter maycomprise a rod element, in particular a rod element made from metal suchas stainless steel. Such a metal rod is likely to provide a stabilitynot provided by a motion transmitter that is completely made of aplastic material. The rod element may in some embodiments be pivotmounted at the functional element, in particular at a mounting locationthat is offset from an axis around which the functional element will bedriven during operation. Alternatively or additionally, the rod elementmay be pivot mounted at a holder element, e.g. a holder element asmentioned above that has a recess that at least partly accommodated thefirst magnetic coupling element. The pivot mounting of the rod elementis likely to support relative movement between the rod element and thefunctional element or the holder element, respectively.

In some embodiments, the attachment section, the protective cover, thefirst magnetic coupling element and/or the motion transmitter has acentering structure that is intended for at least supporting thecentering of the first magnetic coupling element with the secondmagnetic coupling element during an attachment process.

In some embodiments, the first magnetic coupling element may have atleast one indentation or a groove that is filled with plastic material,in particular with injection molded plastic material. E.g. the holderelement mentioned above may be made in a plastic injection molding stepwith the first magnetic coupling element being an insert element. Then,a manufacturing step of e.g. snapping the first magnetic couplingelement into a holder element can be discarded with and further, theinjection molding step may lead to lower clearances or gaps between thefirst magnetic coupling element and the holder element then in case of alater mounting of these two parts.

In an embodiment, the attachment section is arranged such that themotion transmitter is mounted free of any return force elements thatwould influence the behavior of a resonant drive provided in the handlesection with a further spring. As springs typically have tolerances, aspring in the attachment section that is intended for coupling with adrive shaft of a resonant drive in a handle section could contribute tothe spring-mass system that determines the resonance frequency of theresonant drive. Additionally, a spring in the attachment section mayalso produce additional noise in operation due to the tolerance neededfor mounting of the spring. In some embodiments, a handle section forconnection, optionally detachable connection with an attachment sectionas proposed above comprises a second magnetic coupling element arrangedat a drive shaft, which second magnetic coupling element is arranged forestablishing a magnetic connection with a first magnetic couplingelement provided at the attachment section and a second couplingstructure for establishing a connection, in particular a mechanicalconnection (e.g. a force-fit or form-fit connection) with a firstcoupling structure provided at the attachment section, in particular atthe attachment housing. The second magnetic coupling element maycomprise at least a permanent magnet or a magnetizable element.

In at least some embodiments, a handle section as proposed comprises alinear drive (i.e. a resonant drive providing a linear reciprocalmovement or a DC motor having a gear for converting a rotational motioninto a oscillatory linear motion) for driving the drive shaft into alinear oscillation in a longitudinal direction (generally parallel to alongitudinal axis of the drive shaft or coinciding with a longitudinalaxis of the drive shaft). In some embodiments, the linear drive mayprovide via the drive shaft a linear oscillatory motion amplitude in arange of between about ±0.1 mm to about ±2.0 mm, in particular inarrange of between about ±0.5 mm to about ±1.5 mm, optionally in a rangeof between about ±0.75 mm to about ±1.25 mm, further optionally in arange of between about ±0.9 mm to about ±1.1 mm and even furtheroptionally a linear oscillatory motion amplitude of about ±1.0 mm. Insome embodiments, the attachment section comprises a gear assembly thatconverts the linear motion provided by the drive shaft and transferredto the motion transmitter into a oscillatory rotation having a maximumangular deflection in a range of between ±5 degrees to ±40 degrees, inparticular in a range of between about ±10 degrees to ±30 degrees,optionally in a range of between about ±15 degrees to about ±25 degrees,and further optionally of about ±20 degrees (where the angulardeflection is measured in an unloaded state of the functional element).

The longitudinal axis as referred to in all embodiments generallyextends along a longitudinal or lengthwise dimension of the drive shaftor is parallel to a longitudinal axis of the drive shaft or coincideswith a longitudinal axis of the drive shaft. The drive shaft means thedrive shaft of the motor or extensions of that.

In an embodiment, the second magnetic coupling element may have aprotective cover that protects the second magnetic coupling element fromcorrosion. The protective cover may be abrasion resistant to the extentthat during a typical lifetime of the handle section the protectivecover stays intact. As an oral hygiene device is used in a wetenvironment and typically with abrasive and/or corrosive chemicals suchas mouth rinses or toothpaste, a thin coating such as e.g. a 10micrometer thick tin coating may be abraded within a rather shortperiod. A protective cover made of an about 20 μm thick or more,optionally about 30 μm or more, further optionally 40 μm or more, evenfurther optionally about 50 μm or more metal layer, ceramic layer, glasslayer or abrasion-resistant plastic or resin layer may be bettersuitable. In some embodiments, the protective cover may have a thicknessof 60 μm or more, 70 μm or more, 80 μm or more, 90 μm or more, 100 μm ormore, 150 μm or more or 200 μm or more and/or any and/or any thicknesswithin or including the values provided above or any ranges including orwithin the values provided above. The protective cover may be realizedas an essentially cup-shaped element that may be mounted by gluing,press-fitting, crimping, shrink-fitting, stamping, welding, snapping orany combination thereof. The protective cover is, in a particularembodiment, realized as a plate or disk that may be glued to themagnetic coupling element. The protective cover for the second magneticcoupling may be configured similarly to the protective cover describedheretofore with regard to the first magnetic coupling.

In an embodiment, the second magnetic coupling element is at leastpartly accommodated in a recess provided in the drive shaft. In anembodiment, the handle section, the protective cover, the secondmagnetic coupling element and/or the drive shaft may have a centeringstructure that is intended for at least supporting the centering of thefirst magnetic coupling element with the second magnetic couplingelement during an attachment process.

In some embodiments, an oral hygiene device may comprise at least anattachment section as proposed and that may further comprise a handlesection having a second magnetic coupling element and a second couplingstructure for establishing a connection with the first couplingstructure provided at the attachment section. In some embodiments, anoral hygiene device may comprise at least an attachment section asproposed and further a handle section in accordance with a handlesection as proposed in a previous paragraph above. In some embodiments,the handle section comprises a drive having a drive shaft that isarranged to provide a linear oscillating motion during operation and thecontact faces of the magnetic coupling elements are arranged essentiallyperpendicular to the linear movement direction.

In some embodiments, as will be explained in more detail further below,the magnetic coupling between the first and the second magnetic couplingelements is designed to at least partially decouple in case of apull-off force imposed on the magnetic connection that is beyond athreshold force. Such an at least partial decoupling of the magneticcoupling partners is then likely to interrupt the motion transfer and togenerate noise, which can be noticed by a user, who is then informedabout a too high load.

As an example, in case of the oral hygiene implement being an electrictoothbrush and the attachment being a replaceable brush head having as afunctional element a bristle carrier mounted for oscillatory rotation, amagnetic coupling between a motor in a handle section of the oralhygiene device and a motion transmitter in the attachment section shouldbe in a coupled state for typical pull-off forces that occur duringoperation (i.e. brushing of teeth in an example case). Typical pull-offforces that occur during brushing between the first and second magneticcoupling elements may in particular be generated due to friction betweentreatment elements (e.g. bristles) mounted on the carrier and hard orsoft tissue in the oral cavity (e.g. the teeth or the gums). Thisfriction increases with the pressure force with which the functionalelement (e.g. brush head) is applied onto the hard or soft tissue (e.g.the teeth). Typical applied pressure force values may lay in a range ofbetween about 1.5 Newton (N) and about 3.5 N (pressure forces below thisrange are typically either not used or do not lead to a proper treatmentresult and pressure values above this range may potentially lead todiscomfort and even injuries), in particular in a range of between about2 N and 3 N. For the above oscillatory rotating brush heads it has beenfound that the pull-off force that acts at the magnetic coupling maythen be above about 5 N and in particular above about 6 N and furtherparticularly in a range of between about 6.5 N to about 8.0 N. Higherpull-off forces may then be due to a too high pressure force applied bythe user or due to bristles getting stuck in between teeth. In bothcases, it may be reasonable that the magnetic coupling is arranged todecouple at a pull-off force above the maximally occurring and allowedpull-off force. Firstly, it may support to indicate to the user that atoo high pressure force is applied as the decoupling may be noticeableto the user. Secondly, such decoupling is likely to reduce pain that mayoccur in case stuck bristles are pulled out of between the teeth whenthe magnetic coupling would withstand higher pull-off forces. In bothcases it is likely that the decoupling leads to an improved protectionof hard and soft tissue against abrasion and other kind of damage. Thus,a threshold force may be set to 5 N, 5.5 N, 6 N, 6.5 N, 7 N, 7.5 N, 8 N,8.5 N, 9 N, 9.5 N, or 10 N, where in particular the threshold force maybe set to a value of at least about 6.5 N, in another embodiment atleast about 7 N, further in another embodiment at least about 7.5 N andin yet another embodiment at least about 8 N. As will be seen furtherbelow, the threshold force can in particular be set by designing themagnetic coupling accordingly, for example, by choosing the dimensionsof the first and second magnetic coupling elements, choosing therespective materials from which the first and second coupling elementsare made, or choosing a gap between the first and second magneticcoupling elements. While it is here proposed to design the magneticcoupling in a manner that the magnetic coupling decouples in case apull-off force is applied above a threshold force, the above example wasexperimentally derived for bristle carriers mounted for drivenoscillatory rotation at the attachment housing. While it is not excludedthat other functional elements may result in the same threshold force,another threshold force value may be found as preferred based onexperimental investigation with other functional elements or for anotherintended oral hygiene application, e.g. tongue cleaning or gummassaging.

In some embodiments, the attachment section has a first magneticcoupling element that comprises a magnetizable element, which may inparticular be made from stainless steel so that a further protectivecover could be discarded with, which magnetizable element fits into acylinder of at least about 4.5 mm diameter and of at least about 4.5 mmlength. In another embodiment, the diameter may be at least about 5.0mm, in another embodiment, at least about 5.5 mm. In another embodiment,the length may be at least about 5.5 mm, and in another embodiment, atleast about 6.5 mm.

In some embodiments, the handle section has a second magnetic couplingelement that include a permanent magnet, in particular made of NdFeB,which permanent magnet fits into a cylinder of at least about 4.5 mmdiameter and of at least about 4.5 mm length. In another embodiment, thediameter may be at least about 5.0 mm, in a further embodiment at leastabout 5.5 mm. In another embodiment, the length may be at least about5.0 mm, and in another embodiment at least about 5.5 mm.

In some embodiments, the motion transmitter is non-detachably connectedwith the attachment section, in particular with a functional elementmounted for driven movement.

In the following, a detailed description of several example embodimentswill be given. It is noted that all features described in the presentdisclosure, whether they are disclosed in the previous description ofmore general embodiments or in the following description of exampleembodiments, even though they may be described in the context of aparticular embodiment, are of course meant to be disclosed as individualfeatures that can be combined with all other disclosed features as longas this would not contradict the gist and scope of the presentdisclosure. In particular, all features disclosed for either one of thefirst or second magnetic coupling elements may also be applied to theother one.

FIG. 1 is a perspective depiction of an example embodiment of an oralhygiene device 1, here realized as an electric toothbrush. The oralhygiene device 1 comprises a handle section 200 and an attachmentsection 100. Here, the attachment section 100 is realized as adetachable brush section. The attachment section 100 has a functionalelement 130, here realized as a brush head, which functional element 130is movably mounted at an attachment housing 150 such that the functionalelement 130 can be driven into an oscillatory rotation (as shown withdouble arrow 21) around a rotation axis R that may be perpendicular tothe longitudinal axis L of the attachment section 100. Instead of beingrealized as an electric toothbrush, the oral hygiene device may berealized as an (electric) tongue scraper, an (electric) flossing device,an (electric) interdental cleaner etc. The attachment section may thenaccordingly be realized as a tongue scraper section, a flossing section,an interdental cleaning section etc. The functional element may theaccordingly be realized as a tongue scraper head, a flossing head, aninterdental cleaning head etc.

FIG. 2 is a lateral cross sectional cut through the attachment section100 taken along a longitudinal axis of the attachment section 100. Theattachment section 100 comprises the attachment housing 150 and thefunctional element 130, which is movably attached to the attachmenthousing 150.

The functional element 130 may comprise a carrier element 131 on which aplurality of cleaning elements 133 may be mounted for cleaning andmassaging parts of the oral cavity such as teeth and gums. The carrierelement 131 may be mounted to the attachment housing 150 via a mountingaxle 132 for driven oscillatory rotation around a rotation axis R thatmay be essentially perpendicular to the longitudinal axis (referencenumeral L in FIG. 1) of the attachment section 100.

The attachment section 100 may further comprise a motion transmitter 110disposed within a cavity 159 formed within the attachment housing 150.The motion transmitter 110 may be functionally connected with thefunctional element 130 as will be explained in more detail withreference to FIG. 3. Generally and applicable to all embodiments,“functionally connected” shall mean a connection that is not intended tobe disconnected and that shall enable that motion transmitted via themotion transmitter is transferred to the functional element. The motiontransmitter 110 is arranged for transmission of a linear oscillatorymovement to the functional element 130, which linear oscillatory motionmay be generally parallel to the longitudinal axis of the attachmentsection 100 (as indicated by double arrow A). Such a linear oscillatorymotion may be provided by a drive shaft of a handle section when theattachment section 100 is in an attached state, as will be explained inmore detail with reference to FIG. 5.

The motion transmitter 110 may comprise a recess 112 realized as a blindhole provided at a first end 110A that is proximal to the opening of thecavity 159, which opening at the end of the attachment section 100 (i.e.the first end 110A of the motion transmitter 110 is distal to thefunctional element 130). A first magnetic coupling element 120 isdisposed in the recess 112. Generally and, as mentioned above for allthe described features, applicable for all embodiments, the firstmagnetic coupling element 120 may be realized as a permanent magnet or amagnetizable element such as a block of magnetizable iron or steel.Typically, austenitic steel is not magnetizable, while martensitic orferritic steel typically is magnetizable. The first magnetic couplingelement 120 has a coupling side 121 that is oriented towards the openingprovided at the distal end of the attachment section 100. Generally andapplicable to all embodiments, the coupling side 121 may be retractedfrom the opening at the end of the attachment housing intended forcoupling with a handle section so that the magnetic connection isestablished at a longitudinal position inside of the attachment housing,in particular where this longitudinal location is retracted by a valuelying in the range of between about 0.5 cm to about 5.0 cm, e.g. 1.0 cm,1.5 cm, 2.0 cm, 2.5 cm, 3.0 cm, 3.5 cm, 4.0 cm, 4.5 cm or any othervalue lying in the mentioned range from the end of the attachmenthousing and the length of the attachment housing may be in the range ofbetween about 3.0 cm to about 10.0 cm.

The first magnetic coupling element 120 may be secured to the motiontransmitter 110 in any suitable manner. For example, the first magneticcoupling element 120 may be glued to the motion transmitter 110, it maybe snapped into a recess, it may be secured by injection molding atleast a part of the motion transmitter over it or it may be secured byother means as will be explained further below.

In some example embodiments, the first magnetic coupling element isrealized as a magnetizable iron or steel element. In case the firstmagnetic coupling element is realized by a corrosive material such asiron or a NdFeB material (from which relatively strong permanent magnetscan be made), at least the coupling side of the first magnetic couplingelement may have a protective cover to protect the first magneticcoupling element from corrosion.

The protective cover may be realized as a coating, a top cover, a cap ora cup, as will be explained in more detail further below. Generally andapplicable to all embodiments, any protective cover applied to a firstor second magnetic coupling element may lead to a distance between thefirst and second magnetic coupling elements in the attached state andthus to a reduction in the effective coupling force between the firstand second magnetic coupling elements, so that a cover thickness ofabout or less than 0.5 mm, optionally about or less than 0.4 mm, furtheroptionally of about or less than 0.3 mm, even further optionally ofabout or less than 0.2 mm, and yet even further optionally of about orless than 0.1 mm per cover could be chosen. In other embodiments, theprotective cover may comprise a thickness as described previously. Inthe shown embodiment, the first magnetic coupling element 120 is gluedinto the recess. It may have an anti-corrosive coating applied to thecoupling side 121 or a protective cover that may be glued over thecoupling side 121. In the shown embodiment, it would be sufficient tosecure a disc-shaped protective cover onto the coupling side 121 of thefirst magnetic coupling element 120 as the other sides of the firstmagnetic coupling element 120 are protected by the surrounding materialof the motion transmitter 110.

Generally and applicable to all embodiments, the first magnetic couplingelement 120 may be realized as a cylindrical element having its cylinderaxis essentially oriented parallel to the longitudinal axis of theattachment section 100, where the diameter of the cylinder may be chosento be about or larger than about 2 mm, in another embodiment about orlarger about 3 mm, further in another embodiment about or larger thanabout 4 mm, even further in another embodiment about or larger thanabout 5 mm, and yet even further in another embodiment about or largerthan about 6 mm, and/or any number or range including or within thevalues provided. The cylinder element may have any suitable height. Inexample embodiments, the height may be chosen to be about or larger thanabout 2 mm, in another embodiment about or larger than about 3 mm, inanother embodiment about or larger than about 4 mm, in anotherembodiment about or larger than about 5 mm, and yet in anotherembodiment about or larger than about 6 mm, and/or any number or rangeincluding or within the values provided. In some example embodiments,the height of the first magnetic coupling element may be chosen as largeas the diameter. In other embodiments, the second magnetic couplingelement may be designed to have any suitable shape. In such a case, thesmallest possible cylinder into which such a first magnetic couplingelement fits may have a diameter and a height as stated above.

In some example embodiments, the first magnetic coupling 120 is realizedas a permanent magnet. In a case in which the attachment section 100 isa disposable attachment section intended for detachable attachment to ahandle section 200 of an oral hygiene device, material costs may beconsidered as one important aspect. Realizing the first magneticcoupling element 120 and the second magnetic coupling element aspermanent magnets may lead to a relatively high coupling force, whilerealizing the first magnetic coupling element 120 as a magnetizableelement such as an iron or steel element reduces the material costs ofthe attachment section 100.

The attachment section 100 as shown in FIG. 2 may further comprise aninsert element 151 that is snapped into the attachment housing 150thereby forming part of the attachment housing 150. The insert element151 may be equipped with a first coupling structure 152 intended forestablishing a further coupling (i.e. a coupling different to themagnetic coupling that will be established by the first magneticcoupling element 120) with a handle section of an oral hygiene device inan attached state. In the shown example embodiment, the first couplingstructure 152 is realized by mechanical coupling means such as snaphooks or spring elements for clamping projections provided at the handlesection. In other example embodiments, the first coupling structure 152may be realized by a further magnetic coupling element. The longitudinalpositions where the magnetic connection is established and where thefurther connection (e.g. mechanical connection) is established may beseparated, in particular by a distance lying in a range of between about0.5 cm to about 3.0 cm.

FIG. 3 is a transverse longitudinal cross-sectional cut through theexample attachment section shown in FIG. 2, where the viewing directionis towards the cleaning elements. As can be seen from FIG. 3, the motiontransmitter 110 is coupled to the functional element by a coupling pin111 provided at a second end 110B of the motion transmitter 110. Thecoupling pin 111 establishes a coupling with a coupling section 134provided at the carrier element 131 at a position that is eccentric withrespect to the rotation axis defined by the mounting axle 132. When themotion transmitter 110 is driven into a linear oscillatory movement asindicated by double arrow A, then the carrier element 131 will be driveninto an oscillatory rotation around the rotation axis. As will also beexplained further below, in some embodiments, the motion transmitter 110is not associated with any return force element such as a biasing springthat would bias the motion transmitter into a defined rest positionwhenever the motion transmitter is not being driven.

FIG. 4 shows a longitudinal cut through a schematic handle section 200.In the shown example embodiment, the handle section 200 comprises adrive shaft 210 that functions as a movable motor part of a resonantlinear drive 260, which linear drive 260 is disposed within the handlehousing 250. During operation, the linear drive 260 provides for alinear oscillatory movement of the drive shaft 210 as is indicated bydouble arrow B. In the shown example embodiment, the drive shaft 210 maybe prolonged by an extender element 219 that thus forms a part of thedrive shaft 210. The extender element 219 can provide an increase indiameter with respect to the diameter of the drive shaft 210. A recess211 may be provided in the extender element 219 for accommodating asecond magnetic coupling element 220. Instead of being accommodated inthe extender element 219, the second magnetic coupling element 220 mayof course be directly secured at the drive shaft 210 or the drive shaftmay be made at least at its tip portion from a permanent magneticmaterial, which tip would then form the second magnetic coupling element220. The second magnetic coupling element 220 has a coupling side 221intended for getting into contact with the respective coupling side 121(shown in FIG. 2) of the first magnetic coupling element 120 (shown inFIG. 2) of the attachment section when being attached. The coupling sideof the first magnetic coupling element and the coupling side of thesecond magnetic coupling element may be flat or may at least partly benegatives of each other. Generally and applicable to all embodiments,the second magnetic coupling element 220 may be realized as acylindrical element having its cylinder axis essentially orientedparallel to the longitudinal axis of the drive shaft, where the diameterof the cylinder may be chosen to be about or larger than 2 mm,optionally about or larger than 3 mm, further optionally about or largerthan 4 mm, even further optionally about or larger than 5 mm, and yeteven further optionally about or larger than 6 mm or any individualnumber within or any ranges including or within the values provided. Anysuitable height of the cylinder element may be chosen. For example, theheight may be chosen to be about or larger than 2 mm, optionally aboutor larger than 3 mm, further optionally about or larger than 4 mm, evenfurther optionally about or larger than 5 mm, and yet even furtheroptionally about or larger than 6 mm. In some example embodiments, theheight may be chosen as large as the diameter. In other embodiments, thesecond magnetic coupling element may be designed to have any suitableshape. In such a case, the smallest possible cylinder into which such asecond magnetic coupling element fits may have a diameter and a heightas stated above.

Generally, the handle section comprises a handle housing at which asecond coupling structure intended for establishing a connection withthe first coupling structure provided at the attachment section isrealized. In the shown example embodiment, the handle section 200 has ahandle housing 250 comprising a top handle housing section 250A intendedfor coupling with the attachment section and a lower handle housingsection 250B intended to be gripped by a user's hand. Here, the tophandle housing 250A section comprises a top part 251 at which a secondcoupling structure 252 may be realized, The second coupling structure252 can form a further connection, with the first coupling structure 152(shown in FIG. 2) of the attachment section.

In some embodiments, the second coupling structure 252 and the firstcoupling structure may establish a coupling which is different than theconnection established by the first magnetic coupling and the secondmagnetic coupling or the coupling may be similar. For example, thecoupling established by the first coupling structure and the secondcoupling structure may comprise a mechanical lock, magnetic lock, thelike, or combinations thereof. In some embodiments having a top housingsection 250A and a lower housing section 250B, the top housing section250A may be arranged for driven motion, e.g. the top housing section250A may perform an oscillatory rotation around the longitudinal axis, alongitudinal linear vibration, and/or a linear reciprocation along adirection which is generally parallel to a longitudinal axis of thedrive shaft during operation. In such embodiments, the attachmenthousing that is coupled to the top housing section 250A performs a firstmotion during operation, e.g. rotation around the longitudinal axis,longitudinal linear vibration, and/or the linear reciprocation while themotion transmitter may drive the functional element into a secondmotion. The first and second motions are described further with regardto FIG. 5. In some embodiments, the top housing section 250A is notdriven and remains stationary with respect to the lower housing section250B.

FIG. 5 shows a longitudinal cross sectional cut of an attachment section100 and a top housing section of a handle section 200 in an attachedstate. It is shown that the first and second magnetic coupling elements120 and 220 have established a magnetic connection that couples thedrive shaft 210 of the handle section 200 with the motion transmitter110 of the attachment section 100 such that during operation, a linearreciprocation of the drive shaft 210 as indicated by double arrow B willbe transferred to the functional element 130 via the motion transmitter110. In some embodiments, as the transmitted motion is a linearreciprocation, the magnetic coupling does not need to transmit arotational movement so that flat coupling sides of the first and secondmagnetic coupling elements are suitable.

Further, the first and second coupling structures 152 and 252 haveestablished a second connection between the attachment housing 150 andthe handle housing 250 such that the attachment section 100 is fixedwith respect to the handle housing 250. For those embodiments where thetop housing section is driven in an oscillatory rotation around thelongitudinal axis, a longitudinal linear vibration, and/or a linearreciprocation along a direction which is generally parallel to alongitudinal axis of the handle 200, the movement of the top housingsection is transmitted to the attachment housing via the connectionprovided between the first and second coupling structures 152 and 252.

As had been said before, the motion transmitter 110 may be mounted freeof any return force element. It is known to use a return force elementfor a motion transmitter provided in an attachment section in case amechanical connection is to be established between motion transmitterand drive shaft, as then essentially the coupling force needs first tobe overcome during the attachment process. Without a return forceelement, the motion transmitter would potentially be pushed away in theattachment process and the mechanical coupling may not become easilyestablished. For the described magnetic coupling, the first and secondmagnetic coupling elements will attract each other when the attachmentsection is attached to the handle section and the motion transmitterwill then be moved towards to drive shaft so that the magnetic couplingis established without the need to first overcome any resistance. Inparticular for a handle section comprising a resonant drive, where theresonant frequency is dependent on the spring-mass system including areturn-force element such as a spring acting on the motion transmitter,tolerances in the spring would lead to variations in the resonancefrequency of the resonant drive for different attachments. Besides this,discarding a return force element supports a cost efficient manufacture.

Generally and applicable to all embodiments, the first and secondmagnetic coupling elements 120 and 220 may each be realized as apermanent magnet or a permanent magnet arrangement or as a magnetizableelement such as an iron or steel element or an arrangement of suchelements. Any kind of permanent magnet material could be used, e.g. thehigh energy materials SmCo or NdFeB, either realized as sinteredelements or plastic-bonded elements, or any hard ferrite could beutilized such as sintered strontium ferrite. Plastic-bonded permanentmagnet elements tend to have a relatively low magnetic flux density whencompared with e.g. sintered permanent magnets. Sintered NdFeB magnetshave a relatively high magnetic flux density but are also relativelyexpensive and are prone to corrosion. Hard ferrite magnets arerelatively inexpensive and as ceramic materials less prone to corrosionbut have only a limited magnetic flux density. In case that one of thefirst or second magnetic coupling elements is realized as a magnetizableelement, the other one of the first or second magnetic coupling elementsis to be realized as a permanent magnet or permanent magnet arrangement.Permanent magnets are widely available e.g. from IBS Magnet, Berlin,Germany.

In some embodiments, at least one of the first or second magneticcoupling elements is made of or consists at least partially of NdFeBmaterial, in particular of sintered NdFeB material. In some of theseembodiments, the second magnetic coupling element provided in the handlesection is made of or consists at least partially of the sintered NdFeBmaterial. The latter allows for realizing the first magnetic couplingelement as a relatively cheap magnetizable element such as an iron orsteel element or by an arrangement of such elements.

Corrosion-prone permanent magnets like sintered NdFeB magnets maytypically be available from a supplier with a thin anti-corrosivecoating such as a tin or nickel coating. Unfortunately, toothpaste mayabrade these standard coatings rather quickly during operation. Hence,it may then be necessary to equip these permanent magnets with alow-abrasive and anti-corrosive cover to withstand the conditions duringoperation of an oral hygiene device. Various materials may be chosen forthe cover such as low-abrasive plastic materials (e.g. for making adeep-drawn plastic cup), ceramics, metal foils, glass etc.

Some permanent magnet materials such as NdFeB have a low operatingtemperature such as 60 degrees Celsius, which operating temperature isalso dependent on the particular dimensions of the permanent magnet. Forsuch permanent magnets, an anti-corrosive protection may not be appliedby a plastic injection process during which temperatures of 200 degreesCelsius and more may occur as then the permanent magnet may lose itsmagnetization. The protective cover may be applied by casting (e.g. of aresin), gluing (e.g. of a metal, ceramic, or glass disc), snapping,welding etc. as was already mentioned.

The magnetic coupling established by the first and second couplingelements should withstand a typical pull-off force applied at thefunctional element as was explained above so that the magnetic couplingis not separated when such a force is applied. In example embodiments, atypical pull-off force applied at the functional element may be up to 10Newton, i.e. the magnetic coupling should withstand a pull-off force upto a threshold value of about 10 Newton, optionally of up to about 9Newton, further optionally of up to about 8 Newton, even furtheroptionally of up to about 7 Newton, yet further optionally of up toabout 6 Newton, yet even further optionally of up to about 5 Newton, andeven more optionally of up to about 4 Newton or any value within orincluding the values provided.

FIGS. 6A to 6D show four different example configurations S1 to S4 offirst and second magnetic coupling elements. FIG. 7 shows simulationresults for the effective force that exists between the couplingpartners in the coupled state where the results are shown for variousvalues of a gap between the first and second magnetic coupling element,which gap reflects a protective cover on one or both of the magneticcoupling elements.

FIG. 6A shows a first configuration S1 of a first magnetic couplingelement 410A being a cylindrical NdFeB permanent magnet and a secondmagnetic coupling element 420A being a stainless steel cylinder. Thediameter d1 of the NdFeB permanent magnet 410A was set to 5 mm in thesimulations and the height h1 was set to 5 mm. The diameter d2 of thestainless steel element was set to 5 mm and its height h2 was set to 4.5mm. An arrow 419A indicates the magnetization direction of the permanentmagnet that was here set to be along the longitudinal cylinder axis. Thetotal height of the magnetic coupling arrangement is thus 9.5 mm plusgap thickness.

FIG. 6B shows a second configuration S2, where the only difference tothe first configuration S1 shown in FIG. 1 is the magnetizationdirection 419B of the first magnetic coupling element 410B that ischosen to be perpendicular to the longitudinal cylinder axis.

FIG. 6C shows a third configuration S3 of a first magnetic couplingelement 410C and a second magnetic coupling element 420C. The secondmagnetic coupling element 420C is again assumed to be a stainless steelelement, but here having a height of 3.5 mm. The first magnetic couplingelement 410C consists of a NdFeB permanent magnet having a height of 5mm and a diameter of 3.5 mm. The NdFeB permanent magnet is glued into acup-shaped iron container that has an outer diameter of 5 mm and aninner diameter of 4 mm. The iron container consists of a hollow ironcylinder 4104C and a disc-shaped back iron 4103C. The disc-shaped backiron 4103C has a diameter of 5 mm and a height of 1.5 mm Overall heightof the magnetic coupling arrangement is thus again 9.5 mm plus gapthickness. The magnetization direction of the NdFeB permanent magnet4101C is indicated by arrow 419C and is assumed to be along thelongitudinal cylinder axis.

FIG. 6D shows a fourth configuration S4, where the second magneticcoupling element 420D is as in the third configuration S3 a stainlesssteel cylinder having a height of 3.5 mm and a diameter of 5 mm. Thefirst magnetic coupling element 410D consists of a first and a secondhalf-cylindrical NdFeB permanent magnet 4101D and 4102D that areoppositely magnetized in longitudinal direction as is indicated by themagnetization arrows 4191D and 4192D, respectively. The cylinder formedby the two half-cylindrical NdFeB permanent magnets has a height of 5 mmand a diameter of 5 mm. On the backside, the two half-cylindrical NdFeBpermanent magnets are concluded by a back iron 4103D having a disc-likeshape, the disc having a height of 1.5 mm and a diameter of 5 mm Overallheight is again 9.5 mm plus gap thickness.

In the simulations that were performed it was assumed that the remanenceof the NdFeB permanent magnet material is 1370 mTesla. The properties ofstainless steel 1.4021 were calibrated against measurements.

FIG. 7 shows simulation results for the four configurations S1, S2, S3,and S4 described above with reference to FIGS. 6A to 6D. The abscissaindicates the gap between the flat coupling sides of the first andsecond magnetic coupling elements in millimeters. Gap material wasassumed to be air. The ordinate indicates the force between the firstand second magnetic coupling elements in the coupled state in Newton. Itcan be seen that configuration S4 generally leads to the highestthreshold force value of the pull-off force that the magnetic couplingcan withstand, e.g. at 0.1 mm gap configuration S4 leads to a thresholdforce value of about 7.3 Newton at which the first and second magneticcoupling elements would decouple. The other configurations lead to acoupling force of about 3.4 to 4.9 Newton at a gap of 0.1 mm.

FIG. 8 is a schematic cross sectional cut through the top portion of adrive shaft 510 with a second magnetic coupling element 520. In theembodiment shown, the second magnetic coupling element 520 is glued intoa protection cover 525 having a generally cup-shaped form. Theprotection cover 525 has a on its top side, where a first magneticcoupling element 620 indicated by a dashed line would approach thesecond magnetic coupling element 520 during the attachment procedure, acentering structure 526 realized by a raised edge such that a depression527 is formed into which the first magnetic coupling element 620 fits.The raised edge 526 may be tapered towards the approaching firstmagnetic coupling element 620 to support the centering function. Whilethe magnetic coupling as such already has a certain self-centeringfunction, a centering structure supports the centering procedure and canavoid misalignments between the first and second magnetic couplingelements. As has been stated before, the first and second magneticcoupling elements could be interchanged with respect to the featuresdescribed, e.g. FIG. 8 may show an example embodiment of a firstmagnetic coupling element.

Here, the protection cover is realized by a cup that fully accommodatesthe second magnetic coupling element 520 and that at least partlyextends over the drive shaft 510. In such an embodiment, the secondmagnetic coupling element 520 needs not additionally be secured to thedrive shaft 510 as the glue layer 524 fixes the drive shaft 510 and thesecond magnetic coupling element 520. The thickness d3 of the glue layer524 and of the protection cover 525 should be chosen as low as possibleto avoid reduction of the possible coupling force (see FIG. 7). As amatter of fact, the coupling side 521 does not need to be glued to theprotection cover as the side glue layer suffices to establish a fixedconnection. The thickness d3 could be chosen to be about or lower than0.2 mm, optionally to be about or lower than 0.15 mm, further optionallyto be about or lower than 0.1 mm and even further optionally to be aboutor lower than 0.05 mm or any number within and/or any range within orincluding the values provided. The material of the protective covercould be a plastic material, a ceramic, a glass, or a (in particularnon-magnetizable) metal. In an effort to reduce the thickness of theglue layer 524 and the protective cover, embodiments, are contemplatedwhere the glue layer exists only on the sides of the drive shaft 510 andthe second magnetic coupling element 520 but not in between a couplingside 521 of the second magnetic coupling element 520 and a bottom face531 of the protective cover.

A protective cover made of magnetizable material would in the exampleshown in FIG. 8 lead to a magnetic short circuit between magnetic northpole and magnetic south pole of the permanent magnet and the achievableforce between the magnetic coupling elements would be reduced.

FIG. 9 is a schematic depiction of another embodiment showing the topportion of a drive shaft 510A that has a recess 511A that accommodates asecond magnetic coupling element 520A. Bend wall portions 512A fix thesecond magnetic coupling element in the recess 511A. Prior tointroducing the second magnetic coupling element 520A into the recess511A, the wall portions 512A may have been straight to allow insertionof the second magnetic coupling element 520A into the recess 511A. Then,the wall portions 512A may have been bent, e.g. using a forming stamp,such that the second magnetic coupling element 520A is fixed in therecess. A protective cover 525A may cover the remaining opening so thatthe second magnetic coupling element 520A is protected from corrosion.The protective cover 525A may be a resin or any suitable material asdescribed heretofore. In case that the top portion of the drive shaft510A is made of a (non-magnetizable) metal or low-abrasive othermaterial that can be formed in the stamping process, the protectivelayer 525A is effectively protected from being abraded and thus doeshere not necessarily need to have high abrasion-resistance.

FIG. 10 is a schematic depiction of another embodiment showing of thetop portion of a drive shaft 510B and of a first magnetic couplingelement 620B. The drive shaft 510B has a recess 511B that accommodates asecond magnetic coupling element 520B, which second magnetic couplingelement 520B extends above the drive shaft 510B such that a step-likestructure 526B is achieved. A protective cover 525B that may be realizedas a deep drawn plastic cup may be glued with a glue layer 524B over theextending top of the second magnetic coupling element 520B and a toppart of the drive shaft 510B. The first magnetic coupling element 620Bmay comprise a depression 626B that is adapted to the step-likestructure 526B so that the step-like structure 526B and the depression626B cooperate to support the centering of the first and second magneticcoupling elements 620B and 520B in the attachment process. Similar tothe embodiment shown in FIG. 8, the glue layer 524B may be absentbetween a coupling side 521B and a bottom face 531B of the protectivecover 525B in an effort to reduce the gap width between the firstmagnetic coupling element and the second magnetic coupling element. Forthose embodiments where the first magnetic coupling comprise aprotective cap/cover, similar arrangements may be provided.

FIG. 11 is a schematic depiction of the lower portion of a motiontransmitter 610C in which a recess 611C is provided that accommodates afirst magnetic coupling element 620C. The recess 611C may be equippedwith snap noses 612C (here realized with a 90 degrees undercut on theirbackside) so that the first magnetic coupling element 620C that hasrespective depressions is (non-detachably) secured at the motiontransmitter 610C by mechanical means, here realized as snap means. Ontheir frontside (side which is closer to the handle than the backside),the snap noses 612C may be tapered such that the first magnetic couplingelement 620C may be pushed into position (snapped) during manufacturing.The motion transmitter may be realized as a plastic part while the firstmagnetic coupling element 620B may be realized as a non-corrosive steelpart.

In other embodiments, the protective cover realized as a cup similar tothe shown embodiment could be secured at the drive shaft by e.g.crimping, shrink-fitting, welding, or snapping.

FIGS. 12A, 12B, and 12C show various views of another example embodimentof an attachment section as proposed. Identical parts have the samereference numerals in these three views. Reference is made in thefollowing to all three FIGS. 12A, 12B, and 12C. Not all referencenumerals are repeated in all figures.

An attachment section 700 has an attachment housing 750, a functionalelement 730 realized as a brush head mounted at the attachment housing750 for driven oscillatory rotation around a rotation axis R1, whichrotation axis R1 is essentially perpendicular to a longitudinalextension direction of the attachment section 700. The attachmentsection 700 further comprises a motion transmitter 710 that extends in acavity 759 formed inside of the attachment housing 750.

The functional element 730 (here: brush head) has a carrier element 731on which cleaning elements such as bristle tufts may be mounted. Thecarrier element 731 may comprise a coupling element 731A that inparticular may be an integral part of the carrier element 731. Thecarrier element 731 may be mounted at the attachment housing 750 bymeans of a fixation element 738 so that it cannot be easily detachedfrom the attachment housing 750.

The motion transmitter 710 may comprise a holder element 712 and a rodelement 716. The holder element 712 may at least partly accommodate afirst magnetic coupling element 720 in a recess 711 at a first end 710Aof the motion transmitter 710. The rod element 716 may in particular bemade from metal such as stainless steel and may optionally be made froma metal wire. A metal rod element may provide a higher rigidity andelasticity than a respective motion transmitter part made of plasticmaterial. A motion transmitter may be made completely as a singleintegral part from plastic material due to the higher ductility ofplastic compared to metal. The rod element 716 may have a first couplingpart 716A that is pivot-mounted at the holder element 712 and a secondcoupling part 716B that is pivot mounted at a coupling section 739provided at the coupling element 731A of the carrier element 731. Atleast one of the first or second coupling parts 716A, 716B of the rodelement 716 may be a bent rod section that may extend into a bore orblind hole in the holder element 712 or the coupling element 731A,respectively. As can be particularly be seen in FIG. 12C, the firstmagnetic coupling element 720 may have at least an indentation or groove729 that is filled with injection molded plastic 714, i.e. the firstmagnetic coupling element 720 may have been directly overmolded with theholder element 712. This direct overmolding step in the manufacturingleads to minimal gaps or clearances between the first magnetic couplingelement 720 and the holder element 712. Generally and applicable to allembodiments, the first magnetic coupling element may be directlyovermolded with at least a part of the motion transmitter and adepression present at the first magnetic coupling element may be filledwith injection molded plastic material such that the first magneticcoupling element is fixedly secured at this injection molded part of themotion transmitter.

The holder element 712 has protrusions 713 extending in the longitudinalextension direction at the edge of a contact surface 721 of the firstmagnetic coupling element 720, which protrusions may be tapered radiallyoutwards such that these protrusions form a centering structure that atleast supports the centering of the magnetic connection between thefirst magnetic coupling element 720 and a second magnetic couplingelement at a handle section during the attachment of the attachmentsection 700. The centering functionality also performs in an attachedstate when the first and second magnetic coupling elements havedecoupled due to a too high pull-off force and the high pull-off forcehas vanished so that the first and second magnetic coupling elementscouple again due to the magnetic force acting between them. Inparticular in cases where one of the first and second magnetic couplingelements is a magnetizable element, a self centering force as betweentwo permanent magnets is not present and an additional centeringstructure supports to center the two coupling partners and thus tooptimize the coupling force.

In some embodiments, cleaning elements arranged on the attachmentsection may be made from a soft plastic material such as rubber or athermoplastic elastomer (TPE) or may be made from more rigid plasticmaterial such as polyamide (e.g. PA 6.12). Cleaning elements may haveany kind of suitable height, which height may be chosen to lie betweenabout 0.2 mm (e.g. for tongue cleaner structures) and about 30 mm, wherea typical length of a cleaning element may lie in the range of betweenabout 2.0 mm to about 15.0 mm, in another embodiment between about 5.0mm and about 11.0 mm Cleaning elements may have any suitable diameter,which diameter may be chosen to lie in a range of between about 0.2 mmto about 20 mm, and in another embodiment in a range of between about0.5 mm to about 8.0 mm.

Additionally, it should be noted that the cleaning elements may compriseany suitable cleaning element and/or may comprise elements which areutilized for massaging gums, cleaning the tongue, providing chemistry toan area of the oral cavity, e.g. antimicrobial agents, malodor agents,flavor agents, anti-plaque agents, anti-gingivitis agents, whiteningagents, or the like.

For example, in some embodiments, the cleaning elements may comprisetufts. The tufts may comprise a plurality of individual filaments whichare securely attached to the head. Such filaments may be polymeric andmay include, for example, polyamide or polyester. The longitudinal andcross sectional dimensions of the filaments of the invention and theprofile of the filament ends can vary. Additionally, the stiffness,resiliency and shape of the filament end can vary. Some examples ofsuitable dimensions include a length between about 3 mm to about 15 mm,or any individual number within the range. Additionally, the filamentsmay include a substantially uniform cross-sectional dimension of betweenabout 100 to about 350 microns, or any individual number within therange. The tips of the filaments may be any suitable shape, examples ofwhich include a smooth tip, a rounded tip, tapered tip, a pointed tip.In some embodiments, the filaments may include a dye which indicateswear of the filaments as described in U.S. Pat. No. 4,802,255. Someexamples of suitable filaments for use with the brush are described inU.S. Pat. No. 6,199,242. Other suitable examples of bristles includetextured bristles, e.g., single and multicomponent bristles (e.g.,bristles formed by coextruding different polymers), crimped bristles,gum massaging bristles, bristles of varying configurations (e.g.,bristles having multiple lumens), and/or combinations thereof.

Other suitable examples of cleaning elements include those described inU.S. Patent Application Publication Numbers 2002/0059685; 2005/0000043;2004/0177462; 2005/0060822; 2004/0154112; U.S. Pat. Nos. 6,151,745;6,058,541; 6,041,467; 6,553,604; 6,564,416; 6,826,797; 6,993,804;6,453,497; 6,993,804; 6,041,467; and U.S. patent application Ser. Nos.12/008,073, filed on Jan. 8, 2008, entitled, “TOOTHBRUSHES” and60/928,012, filed on May 7, 2007, entitled “ORAL HYGIENE IMPLEMENTS”,all of which are herein incorporated by reference in their entirety.Additionally, any suitable arrangement of cleaning elements may beutilized. Some suitable examples include those described in U.S. Pat.Nos. 5,836,769; 6,564,416; 6,308,367; 6,108,851; 6,058,541; and5,396,678.

In addition to bristles and/or bristle tufts, the cleaning elements mayalso include elastomeric structures, foams, combinations thereof, andthe like. For example, the cleaning elements may comprise elastomericfins as described in U.S. Pat. No. 6,553,604 and U.S. Patent ApplicationPublication No. 2007/0251040A1. As yet another example, the cleaningelements may comprise elastomeric cup shaped elements as described inU.S. Patent Publication No. 2004/0154112A1. In some embodiments, thecleaning elements may comprise a combination of elastomeric elements andbristles. As an example, a combination of fins and bristles may beutilized, a combination of an elastomeric cup(s) and bristles may beutilized, and/or combinations of elastomeric elements either alone or incombination with bristles may be utilized. Combinations of elastomericcleaning elements are described in U.S. Patent Publication No.2009/0007357A1.

The cleaning elements and/or massaging elements may be attached to thehead in any suitable manner. Conventional methods include stapling,anchor free tufting, and injection mold tufting. For those cleaningelements that comprise an elastomer, these elements may be formedintegral with one another, e.g. having an integral base portion andextending outward therefrom or discretely. The elastomer elements may beinjection molded in the head.

In addition to the cleaning elements described heretofore, the head maycomprise a soft tissue cleanser constructed of any suitable material.Some examples of suitable material include elastomeric materials;polypropylene, polyethylene, etc; the like, and/or combinations thereof.The soft tissue cleanser may comprise any suitable soft tissue cleansingelements. Some examples of such elements as well as configurations ofsoft tissues cleansers on a toothbrush are described in U.S. PatentApplication Nos. 2006/0010628; 2005/0166344; 2005/0210612; 2006/0195995;2008/0189888; 2006/0052806; 2004/0255416; 2005/0000049; 2005/0038461;2004/0134007; 2006/0026784; 20070049956; 2008/0244849; 2005/0000043;2007/140959; and U.S. Pat. Nos. 5,980,542; 6,402,768; and 6,102,923.

Additionally, for those embodiments comprise elastomer elements on afirst side of the head and a second side of the head, the second sidebeing opposite the first side, the elastomer elements of both sides ofthe head may be unitarily formed. For example, the head sans theelastomeric elements may comprise openings therethrough which can allowelastomeric material to flow from the first side of the head to thesecond side of the head.

Materials for manufacturing at least a part such as the housing of thehandle section or the housing of the attachment section may be anysuitable plastic or non-plastic material, where typical plasticmaterials may comprise at least one from the group consisting ofpolypropylene (PP), thermoplastic elastomer (TPE), polyoxymethlylene(POM), a blend of polyester and polycarbonate such as Xylex availablefrom SABIC, Saudi Arabia, acrylonitrile styrene acrylateor (ASA),polybutylene terephthalate (PBT). Instead of plastic, metal, glass, orwood may also be chosen as material for making at least a part of theattachment section.

The dimensions and values disclosed herein are not to be understood asbeing strictly limited to the exact numerical values recited. Instead,unless otherwise specified, each such dimension is intended to mean boththe recited value and a functionally equivalent range surrounding thatvalue. For example, a dimension disclosed as “40 mm” is intended to mean“about 40 mm”

Every document cited herein, including any cross referenced or relatedpatent or application, is hereby incorporated herein by reference in itsentirety unless expressly excluded or otherwise limited. The citation ofany document is not an admission that it is prior art with respect toany invention disclosed or claimed herein or that it alone, or in anycombination with any other reference or references, teaches, suggests ordiscloses any such invention. Further, to the extent that any meaning ordefinition of a term in this document conflicts with any meaning ordefinition of the same term in a document incorporated by reference, themeaning or definition assigned to that term in this document shallgovern.

While particular embodiments of the present invention have beenillustrated and described, it would be obvious to those skilled in theart that various other changes and modifications can be made withoutdeparting from the spirit and scope of the invention. It is thereforeintended to cover in the appended claims all such changes andmodifications that are within the scope of this invention.

1. An oral cleaning tool for an electric oral hygiene device,comprising: a housing having a head section with a head cavity foraccommodating a movable oral cleaning head and a neck section with aneck cavity and a handle coupling section; a first magnetic couplingelement including at least a permanent magnet or a magnetizable elementbeing provided in the neck section for mechanical handle drive shaftconnection by magnetic interaction; wherein the first magnetic couplingelement is mounted at a motion transmitter, the motion transmitterextending inside the neck cavity to the head cavity, the motiontransmitter arranged so as to be movable in a linear or longitudinaldirection, and wherein the motion transmitter is coupled with the oralcleaning head, the oral cleaning head arranged so as to oscillate in arotational direction.
 2. The oral cleaning tool according to claim 1,wherein the first magnetic coupling element, the motion transmitter andthe oral cleaning head are arranged and coupled so as to be drivablewith an operation frequency of from about 140 to about 180 Hz.
 3. Theoral cleaning tool according to any claim 1, wherein the first magneticcoupling element is a two component part including a metal and/or aferrous composition that is mounted or in-molded in a plastic element.4. The oral cleaning tool according to any claim 1, wherein the firstmagnetic coupling element has a protective cover that covers at least acoupling side of the first magnetic coupling element that is arrangedfor establishing a magnetic connection.
 5. The oral cleaning toolaccording to claim 4, wherein the protective cover is a cup that ismounted by gluing, press-fitting, crimping, shrink-fitting, welding, orsnapping or any combination thereof.
 6. The oral cleaning tool accordingto any claim 4, wherein the protective cover has a thickness of lessthan about 0.2 mm at the coupling side of the first magnetic couplingelement.
 7. The oral cleaning tool according to claim 1, wherein thefirst magnetic coupling element is provided with a uncovered or blanksurface of a coupling side of the first magnetic coupling element thatis arranged for establishing a magnetic connection.
 8. The oral cleaningtool according to claim 1, wherein the motion transmitter is a rodelement.
 9. The oral cleaning tool according to claim 8, wherein the rodelement is pivotable mounted with either the movable oral cleaning heador with the first magnetic coupling element.
 10. The oral cleaning toolaccording to claim 1, wherein the first magnetic coupling element and/orthe motion transmitter or rod element are provided contact free andspaced in the neck cavity relative to an inner housing wall of the neck,so that the first magnetic coupling element is able to laterally alignwith its coupling partner of a handle.
 11. The oral cleaning toolaccording to claim 1, further comprising a centering structure witheither a tapered protruding side wall or a tapered recessed side wallfor mechanical connection of the housing independent from the mechanicalconnection provided by the first magnetic coupling element.
 12. A handlesection of an electric oral hygiene device comprising: a linear driveincluding a drive shaft for oscillation along a longitudinal axis or ina longitudinal direction of the handle at which a second magneticcoupling element is arranged, having at least a permanent magnet whichprotrudes from the handle and that is embedded with respect to at leastthree sides thereof in a hard and/or soft plastic handle body and afurther mechanical oral cleaning tool coupling section that is arrangedto provide independent coupling with the oral cleaning tool.
 13. Thehandle section according to claim 12, wherein the second magneticcoupling element has a protective cover that covers at least a couplingside of the second magnetic coupling element that is intended forestablishing the magnetic connection.
 14. The handle section accordingto claim 12, further comprising an oral cleaning tool coupling sectioncomprising a centering and rotational alignment structure with either atapered protruding side wall or a tapered recessed side wall forcentering and rotational aligning the oral cleaning tool relative to thehandle.